Investment Casting of Titanium Alloys

Home , Chemical milling

Lighter, greener and as strong: Developing light metals for application in the aerospace industry

Willie du Preez

31 August 2010

www.csir.co.za © CSIR 2010 Slide 1 Outline of presentation

• Introduction • Drivers of the International Titanium Industry • Drivers of the South African Titanium Industry

• The South African Innovation Opportunity

• The Titanium Centre of Competence

• Titanium Processing • Investment casting • Near-net shaping of powder

• Semi-Solid Metal Casting of Aluminium alloys

• Conclusions

Cold War: Titanium in military aircraft (USA) Titanium in submarines (USSR)

Space Missions: Titanium in satellites Titanium in launch vehicles

Commercial Aircraft: From less than 4% in Boeing 747 to >17% in Boeing 787 Similar increase for Airbus Growth of >50% over next decade

The SR-71 Blackbird Designed & built in 1959 - 1963

Fastest airplane ever: Mach 3.2 (3700 km/h) at 80 000 ft ~ 24 km New York - Londen: 1h 55min

Fuselage skin temperature: 200º - 370ºC Needed to be lightweight

Constructed for 90%+ from Titanium alloys

50 million pounds Ti used during development 67 tonnes per SR-71

SA’s Space Programme (mid ’80s – mid ’90s): Titanium (Ti-6Al-4V) in satellites

Medical applications (’90s – present): Titanium orthopaedic implants Titanium dental implants

Chemical processing: Commercially pure Titanium in processing plants (corrosion resistance)

Commercial aircraft industry needs: Boeing’s need for alternative suppliers Growing relationship with Airbus

Technologies: Design & analysis Die design & production Forging Superplastic forming Machining Electron beam welding Laser welding Non-destructive testing (X-Ray microfocus)

Satellite fuel tanks put to the test, Engineering News, Vol12 No.42 (Oct 30 – Nov 5 1992)

Slide 6 © CSIR 2010 www.csir.co.za South African Ti-6Al-4V products of the early 1990s

Technologies: Design & analysis Die design & production Forging Machining Hydroxyapatite coating

F A Weber, W B du Preez and N D L Burger, Development and use of the Hybrid stem for upper femoral bone loss in hip revision surgery , Geneeskunde, Vol 35, No 3, (May 1993) p 14 Slide 7 © CSIR 2010 www.csir.co.za Titanium Content per Airframe (J. Monahan, ITA Conference, 2006) 16 B787 14

10 B777 A380 A350 8

Mass % % Mass Mass B747 6 B757 B737 4 B747 2 B727 A300 B767 0 1950 1960 1970 1980 1990 2000 2010 2020 The South African Innovation Opportunity

Existing markets: Aerospace Automotive Significant Primary Medical Component Ti ore metal and mill Recreational manufacturing reserves product Industrial technologies technologies (e.g. Power plants) Chemical

Raw material Processes & technologies Market

The Titanium Centre of Competence integrates and coordinates R&D and commercialisation across the value chain

Supplier Development

Industrialisation & Commercialisation

Technology Development Primary Powder Based Investment Machining Additive Joining Titanium Titanium Metal Processing of Casting of Titanium Manufacturing of Titanium Mill Production Titanium of Titanium of Titanium Products US NMMU CSIR CSIR CSIR UJ CUT NLC Mintek NIMS (Japan) UCT UCT NLC CPUT Forming UP, Necsa ULIM, WITS, SU US Aerosud Aerosud & Forging Thermtron Mintek, CUT, NLC Boeing CSIR VUT of Titanium

Physical Metallurgy of Titanium: UP, UCT Simulation and Modelling: ULim(Ab Initio), CSIR(FEM, ProCast, Ab Initio), UCT(FEM, Proc. Mod.), CPUT(Weld Sim)

Laboratories & R&D Facilities: CSIR, UCT, UP, US, NMMU, CUT, Mintek, Necsa, NLC

R&DR&D Platforms Platforms www.csir.co.za © CSIR 2010 Slide 10 Titanium Centre of Competence Collaborators

International

R&D Institutions: NIMS (Japan) ULim Univ California (USA) UP Aerosud ESRF (France) Necsa Univ of Birmingham (UK) CSIR Mintek Univ of Plymouth (UK) NLC ALD (Germany) UJ Wits VUT Industry Players: Snecma (France) Airbus (France) CUT Boeing (USA) UKZN

UCT SU NMMU CPUT

• Only a few players in the world can cast Titanium successfully on commercial scale

• They handle this as proprietary knowledge and do not publish detail

• CSIR had to develop the key processes in the casting process chain

• We upgraded facilities used successfully in the 1990s for casting turbine blades in Nickel-based superalloys, to enable us to investment cast Titanium alloys

• Developed and packaged the Titanium mouldmaking and crucible melting processes

• Developed and packaged the chemical milling process

• Casting an aerospace part

• Our primary Titanium metal production process delivers a Titanium powder

• More affordable Titanium powder will unlock a much broader market for Titanium products produced from powder

• Therefore we have been developing a Titanium powder processing competence since 2006

• Through strong support from the DST we have been ale to acquire essential equipment

• Establishment of our metal injection moulding process with first test samples

• Patent on novel Ti -Mg alloys via direct reduction of TiO 2 Mixture of TiO & Mg HEBM / MA / RM oxides & Leaching TiMg 2 TiMg

• Compaction and sintering of powder produced through the CSIR process 18

8 % Channel % 6

0 1 10 100 1000 10000 Particle size (um)

T-i6Al-4V (2% Licowax) Ti-30Mg (2% Licowax) © CSIRTi-6Al-4V (2% Licowax) 2006 milled 1hr Primary Ti (CSIR) www.csir.co.za© CSIR 2010 Slide 15 Semi-Solid Metal Casting of Aluminium

Development of the CSIR Rheocasting System Establishment of a High Pressure Die Casting cell Redesigned an automotive component for SSM forming

SSM Forming of Aluminium Alloys Casting Alloys: A356 A201/206 Wrought Alloys: 7075

Establishing an HPDC facility with the capability to perform short production runs (industrial simulation)

Dosing Furnace SSM billet machine

650 Ton LK shot control die casting machine

• The Titanium Centre of Competence has successfully aligned Titanium related R&D across the country and focused these strongly on needs of the aerospace industry

• The Investment Casting process for Titanium castings has been successfully developed and packaged and the commercialisation effort has started

• The patented CSIR Rheocasting technology for semi-solid metal casting of high strength Aluminium alloys is also ready for commercialisation and offers interesting opportunities for aerospace application

I would like to acknowledge the contributions of my colleagues and their research teams:

• Investment Casting: Pierre Rossouw

• Powder Based Processing: Dr Hilda Chikwanda

• Semi-Solid Metal Casting: Dr Sagren Govender